The present invention relates to a new and improved construction of a pressure exchanger cell ring--also referred to in the art as a gas-dynamic pressure wave machine--which is of the type wherein the rotor thereof, when viewed in cross-section, possesses cell walls of at least double curvature which are attached to the hub and shroud of the rotor, and each cell wall curves to both sides of a radius extending from the center of the rotor through one of the two attachment points or locations of the cell wall. The invention further relates to a novel construction of cell wall for use in a pressure exchanger cell ring.
A pressure exchanger cell ring has been disclosed in British Pat. No. 1,077,365, published July 26, 1967, which, when viewed in cross-section, possesses doubly curved cell walls, wherein the two surfaces enclosed by the means camber line and the chord line joining the two points of attachment, and which points of attachment are not located along a radius extending through the center of the rotor, are identical. The teaching of this patent is significantly silent as to how pronounced the curvatures of the lobe or curved portions should be, or may be, and equally as to what would be a maximum permissible value of the spacing between the mean camber line and the chord or connecting line. Cell walls of this type provide certain beneficial operating characteristics as concerns the thermal stresses which arise, yet no consideration is given to the quite appreciable mechanical stresses caused by centrifugal forces and exerted in the cell walls and at their attachment points or locations.
Furthermore, a pressure exchanger cell ring has been taught in Swiss Pat. No. 458,839 possessing a construction wherein, each cell wall, viewed in cross-section, curves to either side of the radius passing through at least one of its two points of attachment. These curved portions are coordinated to one another in a manner such that for the attachment point or location lying on the radius the resultant centrifugal moment is aproximately null. This is also true for both points of attachment provided that they are located on the same radius, yet in this case the thermal stresses are considerable. If the cell wall is curved to each side of the radius passing through only one of the points of attachment, then, while the thermal stresses in the cell wall are very small, nonetheless the mechanical stresses at the other attachment point or location are high and the restoring forces acting upon the cell wall are considerable. This patent is equally notably silent as to maximum permissible curvature values of the curved portions or lobes.